1. Field of the Invention
The present invention relates to a vibratory linear actuator and an electric toothbrush using the same.
2. Description of the Related Art
One example of a vibratory linear actuator, specifically for preferable use as a driving source of an electric toothbrush has been known as composed of a cylindrical stator having a winding wire, a cylindrical movable element that is provided with a member made of a magnetic material and disposed inside the stator, and a shaft attached on the movable member (See Japanese Patent Application Laid-open Publication No. 2002-176758).
In addition, there has been known another vibratory linear actuator that is provided with a vibration absorbing weight moving independently from the movable member to reduce or offset unwanted vibration in order to eliminate a disadvantage of vibration caused by inertial force of the movable member (See Japanese Patent Publication No. 3475949).
However, when the vibration absorbing weight moving in opposite phase to the movable member is used to reduce vibration, the vibratory linear actuator inevitably becomes larger in size. In addition, since the use of the vibration absorbing weight leads to an increased weight of moving components including the movable member and the weight, more energy is required to reciprocate the components.
Therefore, an electric toothbrush using such a vibratory linear actuator also has disadvantages in terms of downsizing and energy saving.